In a coordinate input device that detects an input made by a user's hand or finger, an electrostatic capacitance type, which is capable of detecting simultaneous inputs made by a plurality of indicators, that is, easily detecting multi-touch events, is currently mainstream. The electrostatic capacitance type coordinate input device detects an input position by utilizing a minute change in electrostatic capacitance, so that detection resolution is not high, and thus the detection accuracy of an input coordinate is low. Thus, coordinate input devices of an electromagnetic induction type having higher detection accuracy are used for character writing or picture drawing. In the electromagnetic induction type coordinate input devices, a coil is embedded into an indicator, and an induced electromotive force from the coil driven by a drive line provided in a detection surface is detected by a detection line, whereby an indicated position is detected.
For example, Patent Document 1 discloses a coordinate detection device capable of detecting an indicator by either the electromagnetic induction type or electrostatic capacitance type. This device is realized by laminating an electromagnetic induction type pen detection unit and an electrostatic capacitance type finger detection unit with a display device interposed therebetween.
Further, Patent Document 2 discloses a device capable of detecting a position of an oscillating pen as a digitizer as well as detecting a position of a finger as a touch panel. When operating as the digitizer, the device oscillates a predetermined carrier signal from the oscillating pen and detects the carrier signal from individual electrode lines. When operating as the touch panel, the device provides a carrier signal similar to the carrier signal from the oscillating pen to an arbitrary electrode line. Then, an electric field occurs between orthogonal electrode lines by capacitive coupling. When a finger approaches the touch panel, a signal from the electric field is absorbed by the finger to cause a capacitance change. This capacitance change is utilized to detect the finger.